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I have considered that, always confused, and spoken to him. He is the least stressed person I know, generally. He is very happy with friends at school, he doesn't drink. I've bought him a beer twice so he can try it and hopefully learn in moderation. His sister has tried cannabis and he lectured her about it. He is finding A-levels harder than he expected though. But I have pointed out it is his choice to be at school at his age and that if he wants to work instead, it's up to him and not to make himself ill over it.
many thanks alwaysconfused and sqad. Will keep on with diary and take him back to doc. X